Photographic developers containing sulfa compounds



United States Patent Ofifice Patented Feb. 28, 1967 3,306,746 PHOTOGRAPH-EEC DEVELOPERS CONTAINING SULFA 'COMPGUNDS Moses A. Schwartz, 1674 Townsend Ave, Bronx, N.Y. 10453; Harriet S. Schwartz, executrix of said Moses A. Schwartz, deceased No Drawing. Filed Aug. 20, 1965, Ser. No. 481,413 13 Claims. (Cl. 9665.5)

This invention relates to a new and improved developing solution and a new and improved process for the development of a silver halide emulsion.

Developing photographic films having silver halide emulsions yielding negatives having silver grains by means of developing solutions or developers are well known in the art. However, it has been found that many disadvantages have occurred through the use of the conventional and well known developing solutions or developers in developing photographic films, particularly X-rays, having gelatino silver halide emulsions. This has been shown by the fact that through the use of these developers for developing solutions there is a tendency for considerable lack of clarity, contrast, and the like to result in the developed film through the use of the existing developers or developer solutions under the temperature conditions necessary for developing photographic films. This is true, since in utilizing any of the conventional developers or developing solutions for silver halide emulsions, it is necessary to maintain the temperature during the development process at about 68 F. (18 C.). If there is any serious departure from this temperature, it has been found that fogging as well as lack of clarity and contrast results in the developed film, causing the film to be rendered useless. Hence, in utilizing developing solutions for developing films containing silver halide emulsion, it is necessary to carry out the developing procedure within a narrow temperature range, i.e., about 65 F. (18 C.).

While this fogging of photographic films during developing is particularly troublesome in connecting with such conventional photographic work such as portraits, newspaper pictures, etc., this fogging is most troublesome in developing X-ray films, as in dental and surgical medical practice. In the latter case, sufficient lack of contrast or clarity in the developed film may easily make suitable diagnosis of the conditions impossible, or at best, difficult. In this manner, treatment or operative procedure of the condition may be delayed while photographs are being taken. In order to prevent this fogging from occurring in X-ray films, it has been found necessary for the operators of X-ray apparatus to resort to elaborate means for controlling temperatures of their developing solution so that the temperature falls within the very narrow range of about 68 Fahrenheit. Furthermore, operators must exercise extreme care in the developing process itself to avoid overdevelopment and other difficulties.

In order to combat the fogging which occurs when temperatures other than the specific temperature is utilized in the developing procedure, various additives such as ureas and substituted ureas have been added to developing solutions. While these additives have been to some degree successful as anti-fogging agents and as allowing wider temperature ranges in the developing procedure to be utilized, they have not been successful in the developing of X-ray films. This is shown by the fact that while they do permit wider temperatures to be utilized in the developing procedure, they do not provide the clarity and contrast when wider temperature ranges are utilized. In the developing of photographic films, a high degree of clarity and contrast is not of prime importance, but in the developing of X-ray films, the lack of sutficient contrast or clarity in the developed film can render the film worthless in order to make a suitable diagnosis of a physical condition, so that treatment or operative procedures may be performed. Therefore, in the field of X-rays, it is essential that the developed X-ray film have good contrast as well as sufficient clarity.

Therefore, it is an object of this invention to provide a novel and improved developing solution for films, particularly X-ray films, which affords vastly improved clarity and contrast, and substantially eliminates fogging of the developed film.

Another object of this invention is to provide a novel and improved method of developing films having silver halide emulsions which produces films having vastly improved clarity and contrast without fogging.

It is a further object of this invention to provide a new and novel developing solution which can be utilized to develop films under conditions Where the temperature of the solution may vary between wide limits without loss of clarity or contrast in the developed film, and without the danger of fogging.

It is a further object of this invention to provide a novel and improved developing solution which has relatively long life and will not substantially deteriorate or lose its developing capacity under storage conditions.

It is a further object of this invention to provide a developing solution for developing films, particularly of the X-ray type, which will increase the speed of development and improve the gradation and contrast of the developed film while wide temperature ranges are utilized during the development procedure.

It is still a further object of this invention to provide a new and novel developing solution which can contain any conventional developing agent which can produce developed film of vastly improved clarity and contrast without the danger of fogging.

These and other objects and advantages of the invention will become apparent from the following detailed description of the invention.

It has been found that the development of film having a light exposed gelatino silver halide emulsion in the presence of sulfamethylthiadiazole, which has the following structural formula:

or other sulfa compounds such as sulfadiazine, sulfanilamide, sulfapyridine and sulfathiazole or mixtures thereof can be carried out utilizing wide temperature ranges i.e., about 40 F. to about F. to produce developed films having improved clarity and contrast and free of fogging, utilizing shorter times than have heretofore been utilized in developing films. These results are accomplished by adding such a compound to a developing solution used for the development of exposed gelatino silver halide emulsions. Furthermore, if the filmis left for long periods of time in the developing solution containing the aforementioned sulfur compounds in accordance with this invention, after the development process has been completed, it has been found that the film will not unduly darken and the results will remain good as a result of the self-stopping action produced by utilizing this compound in the developing solution. Additionally, it has been found that by means of utilizing this compound in connection with the development of films, especially X-ray films, relatively cheap and poor quality films can be utilized without any deleterious effects being suffered thereby. This is true since by utilizing this compound in accordance with this invention, it has been found, that any type or quality of film may be developed whereby a developed film of good quality, good contrast, and good clarity will be obtained. Also, it has been found that developing solutions which contain the aforementioned sulfa compounds have a relatively long life and will not substantially deteriorate or lose their developing capacity even under prolonged storage conditions. Furthermore, by utilizing the sulfa compounds in accordance with this invention, it is found that X-ray films can be developed utilizing wide temperature ranges of from about 40 Fahrenheit to about 95 Fahrenheit, so as to produce a developed film having improved clarity and contrast without fogging so that the film may easily be utilized to make suitable diagnosis of physical conditions so that treatment or operative procedure can be easily prescribed. Therefore, by means of this invention, X-ray apparatus operators need not resort to elaborate means for controlling temperatures of their developing solutions within narrow limits, nor need they exercise extreme care in the developing process itself, so as to avoid overdevelopment or other difficulties. The new and improved beneficial results obtained in developing films which have exposed gelatino silver halide emulsions in the presence of the sulfa compounds of this invention are not dependent on the use of any particular type of developing agent. Any developing agent for developing light exposed gelatino silver halide emulsions may be utilized in accordance with this invention. Typical developing agents which may be utilized in accordance with this invention include p-methylaminophenol, hydroquinone, pyrogallol, pyrocatechin, diphenyl amine, paraaminophenol, diaminophenol, etc., and mixtures thereof. These developing agents are generally utilized in aqueous solutions in amounts of at least 1 gram per gallon of water and preferably from about 1 gram to about 100 grams per gallon of water.

Generally, the developing agent is applied to develop the photographic film containing the light-exposed gelatino silver halide emulsion in the form of an aqueous solution. These solutions usually containing alkalies, in an amount of at least 45 grams per gallon of said developing solution so as to neutralize the halogenated acids given off during the reaction of the developer and the gelatino halide emulsion. For best results, water soluble alkali metal salts capable of producing a pH of at least 8 when dissolved in water should be utilized as the alkali medium in the developing solution. Typical salts which are commonly used as the alkali medium in developing solutions include potassium bromide, sodium carbonate, potassium meta-bisulfite, sodium sulfite, sodium carbonate, sodium meta-borate, ammonium carbonate, sodium bicarbonate, potassium bicarbonate, trisodiumphosphate, tripotassiumphosphate, etc., as well as mixtures thereof. In accordance with this invention any conventional alkali or alkali metal salts may be utilized in the developing solution.

The sulfamethylthiadiazole or any of the other aforementioned sulfa compounds may be added to the developing solution at any time before the developing solution is utilized to develop the photographic film containing the light exposed gelatino silver halide emulsion. In order to produce the beneficial results of this invention the sulfamethylthiadiazole compound or any of the other sulfa compounds, should be present in an amount of at least 0.1 gram per gallon of developing solution. Any amount of these sulfa compounds may be present in the developing solution so long as this amount is at least 0.1 gram per gallon of developing solution. Generally, if desired, 300 grams of these sulfa compounds per gallon of developing solution may be utilized in accordance with this invention. However, optimum results are achieved by utilizing these sulfa compounds in an amount of from about 0.16 gram per gallon to about 0.3 gram per gallon. Furthermore, it is preferred to add the sulfa compound during the preparation of the developing solution, since it has been found that these compounds prevent the deterioration of the developing solution even after relatively long periods of storage. Best developing results, it has been found, are achieved by use of sulfamethylthiadiazole, however, very good results are also achieved by use of sulfadiazole sulfanilamide, sulfapyridine, or sulfathiazole or mixtures thereof. Therefore, by incorporating these compounds into the developing solution during the formation of the developing solution, the developing solution will have a relatively long life. On the other hand, the sulfa compounds may be added to a commercially available developing solution just be fore the step of developing a photographic film is to be carried out. This is true, since it has been found that any conventional developing solution which contains the sulfa compounds, in accordance with this invention, will produce the aforementioned beneficial results.

In utilizing the composition of this invention, a film which has been exposed to light is developed in a solution containing these sulfa compounds. After developing has been complete, which has been found to be much shorter in time than with other known developing solutions, the film is then rinsed in water for a suitable period of time, such as about one minute or so, as is well known in the art. Generally, by utilizing these sulfa compounds in accordance with this invention, complete developing of photographic films can take place within a period of about two to about two and one-half minutes. After rinsing, the film is then placed in a fixing solution, of any type well known in the art, such as, for example, any standard X-ray fixing solution when X-ray films are being developed. Following fixing, the usual washing period in water takes place, which might be, as is well known, about thirty minutes to about eighty minutes, depending upon conditions as is understood in the art.

It has been found that by utilizing the developing solution in accordance with this invention the temperatures during the step of development of the present invention can vary widely without undue change in the good results expected therefrom. Whereas, with other known developing solutions, the temperature of the solution is quite critical, and if it varies much from what is considered a normal range, the results may be expected to be quite poor, indeed, if not usable. Thus, in developing dental X-ray films, with an exposure time of about one-quarter second, with 60 kilovolts at 10 millianiperes on the X-ray tube, the films were developed with developing solution temperatures ranging from about 45 F. to about F. with very good results and fine clarity and contrast throughout the range mentioned. The films were all ready, fully developed, in a developing time of about two to about two and one-half minutes throughout the temperature range mentioned, and were found to be free of fogging. The short developing time may be contrasted with the usual developing time recommended for the commercial developing solutions of about five minutes. The use of the developing solution of this invention permits the technician to process his films much faster and without the sacrifice of quality. In fact, the results were characterized by uniform substantial improvement in the quality of films developed, which allowed suitable and easy diagnosis of existing conditions of the teeth and surrounding structure and tissues in the mouth.

It has been found that developing solutions made according to the teachings of this invention are inherently self-stopping to a high degree, and thus prevent inadvertent over-development if not quickly taken out of the developer, as would almost certainly occur with exist ing known developers. Thus, as mentioned, with an elevated temperature of the developing solution, such as about 76 F., the increased temperature hastens the de veloping action where existing solutions are used. Hence,

for example, it has been found that at 86 F. in many known developing solutions, if the film is left in the developing soltuion after development for as much as two minutes, the film becomes quite black or dark and practically indiscernible due to over-development. On the other hand, with the improved developing solution as taught herein, a film left in a solution at even 95 F. for much longer than two minutes will not become dark to any appreciable or harmful degree and will give good clarity and contrast even at such elevated temperatures and after a long time of remaining in the developing solution.

In accordance with a preferred embodiment of this invention, the developing solution may contain, if desired, borax, which has the formula Na B O- :lH O. The use of the borax seems to introduce a detergent action, helping the. developing solution to penetrate the silver halide gelatino film and to reach the silver salts faster and in a more even manner; in this manner developing of various portions of the film may be carried out more quickly and uniformly. If borax is desired to be added to the developing solution, it should preferably be added in an amount of from about grams per gallon of developing solution to about 100 grams per gallon of developing solution. While it is preferred to add borax, the benefit of utilizing the sulfamethylthiadiazole in accordance with this invention can be achieved without utilizing borax. Therefore, if desired, the developing solution need not contain borax.

The following examples serve to illustrate the invention which, however, is not limited thereto.

Example 1 A developing solution was made up as follows:

' G. Metol (p-methylaminophenol) 3.5 Sodium sulfite, anhydrous 60 Hydroquinone 9 Sodium carbonate, monohydrated 40 Potassium bromide 2 Enough water was added to this mixture so that a solution of one-half gallon was formed. To this solution there was added 26.33 g. of borax. Two separate batches of this developer were made up, one being used without further additions or dilutions as a blank; to the other there was added about 0.125 g. of sulfamethylthiadiazole. Exposed X-ray films having the same degree of exposure were developed in each of the solutions. In the case of the blank solution, development was carried out at 68 F. In the case of the solution having the addition of the sulfamethylthiadiazole, development was carried out at a temperature which ranged anywhere from about 45 Fahrenheit to about 90 Fahrenheit. No attempt was made to keep this temperature range constant, and the temperature was allowed to range anywhere in between these two limits. The time of development for the blank was about five minutes; whereas, the time for development of the developing solution containing the sulfamethylthiadiazole was about two minutes. It was observed that the film developed with the developer containing sulfamethylthiadiazole was developed to the same contrast and clarity as the film which was developed at the normal temperature in the blank developer. Furthermore, there was no fogging in the film that was developed with the developing solution containing the sulfamethylthiadiazole. In fact, the results obtained by utilizing the developing solution containing sulfamethylthiadiazole were characterized by a uniform substantial improvement in the quality of the film developed, leading them to suitable diagnosis of the existing conditions of the teeth and surrounding structures and tissues.

6 Example 2 A developing solution was made up as follows:

Pyrogallol g 0.5 Sodium sulfite crystals g 5.0 Potassium meta-bisulfite crystals g 0.5 Sodium carbonate crystals g 5.0 Potassium bromide g 0.06 Water cc 100 Two separate batches of the above developer were made up, one being used without further additions or dilutions as a blank; to the other there was added about 0.1 g. of sulfamethylthiadiazole. Exposed X-ray films having the same degree of exposure were developed in each of the solutions. In the case of the blank solution, development was carried out at 68 Fahrenheit. In the case of the solution having the addition of the sulfamethylthiadiazole, development was carried out at a temperature which ranged anywhere from about 45 Fahrenheit to about Fahrenheit. No attempt was made to keep this temperature range constant, and the temperature was allowed to range anywhere in between these two limits. The time of development for the blank was about five minutes; whereas, the time for development of the developing solution containing the sulfamethylthiadiazole was about two minutes. It was observed that the film developed with the developer containing sulfamethylthiadiazole was developed to the same contrast and clarity as the film which was developed at the normal temperature in the blank developer. Furthermore, there was no fogging in the film that was developed with the developing solution containing the sulfamethylthiadiazole. In fact, the results obtained by utilizing the developing solution containing sulfamethylthiadiazole were characterized by a uniform substantial improvement in the quality of the film developed, leading them to suitable diagnosis of the existing conditions of the teeth and surrounding structures and tissues.

Example 3 A developing solution was made up as follows:

Hydroquinone cc 750 Sodium carbonate g 40 Sodium meta-borate g 10 Sodium sulfite g 5.0 Potassium bromide g 0.06

Enough water was added to this mixture so that a solution of one-half gallon was formed. Two separate batches of this developer were made up, one being used without further additions or dilutions as a blank; to the other there was added about 0.125 g. of sulfamethylthiadiazole. Exposed X-ray films having the same degree of exposure were developed in each of the solutions. In the case of the blank solution, development was carried out at 68 Fahrenheit. In the case of the solution having the addition of the sulfamethylthiadiazole, development was carried out at a temperature which ranged anywhere from about 45 Fahrenheit to about 90 Fahrenheit. No attempt was made to keep this temperature range constant, and the temperature was allowed to range anywhere in between these two limits. The time of development for the blank was about five minutes; whereas, the time for development of the developing solution containing the sulfamethylthiadiazole was about two minutes. It was observed that the film developed with the developer containing sulfamethylthiadiazole was developed to the same contrast and clarity as the film which was developed at the normal temperature in the blank developer. Furthermore, there was no fogging in the film that was developed with the developing solution containing the sulfamethylthiadiazole. In fact, the results obtained by utilizing the developing solution containing sulfamethylthiadiazole were characterized by a uniform substantial improvement in the quality of the film developed, leading them to suitable diagnosis of the existing conditions of the teeth and surrounding structures and tissues.

Having now fully set forth and described my invention, what I claim as new and desire to have secured by Letters Patent is:

l. A process for the development of gelatino silver halide emulsion which comprises developing such an emulsion in a developing solution containing a sulfa compound selected from the group consisting of sulfarnethylthiadiazole, sulfanilamide, sulfapyridine and sulfathiazole or mixtures thereof, in an amount of at least about 0.1 gram per gallon of said developing solution.

2. A process for the development of gelatino silver halide emulsion which comprises developing such an emulsion in a developing solution containing at least about 0.1 g. of sulfamethylthiadiazole per gallon of said developing solution.

3. A process for the development of a gelatino silver halide emulsion which comprises developing such an emulsion in a developer containing from about 0.1 gram to about 300 grams of a sulfa compound selected from the group consisting of sulfamethylthiadiazole, sulfanilamide, sulfapyridine and sulfathiazole or mixtures thereof per gallon of developing solution, and from about 10 grams to about 100 grams of borax per gallon of developing solution.

4. The process according to claim 3 wherein said sulfa compound is sulfamethylthiadiazole.

5. A process for the development of gelatino silver halide emulsion which comprises developing such an emulsion in a developer containing from about 0.1 gram to about 70 grams per gallon of said solution of sulfamethylthiadiazole.

6. The process of developing a gelatino silver halide emulsion which comprises developing such emulsion in an aqueous developing solution containing a developer, at

least about grams per gallon of a water soluble alkali metal salt capable of producing in water a pH of at least 8, and sulfamethylthiadiazole in an amount of at least about 0.1 gram per gallon of said developing solution.

7. A photographic developer solution comprising an aqueous solution containing a gelatino silver halide developer, and at least 0.1 gram per gallon of said developing solution, of a sulfa compound selected from the group consisting of sulfamethylthiadiazole, sulfanilamide, sulfapyridine and sulfathiazole or mixtures thereof.

8. A photographic developer solution comprising an aqueous solution containing a gelatino silver halide developer, and at least 0.1 gram per gallon of said developing solution of sulfamethylthiadiazole.

9. A photographic developing solution comprising an aqueous solution containing a gelatino silver halide developer, at least about 45 grams per gallon of said solution of a water soluble alkali metal salt capable of producing a pH of at least 8 in water, and at least 0.1 gram per gallon of said solution of sulfamethylthiadiazole.

10. The composition of claim 9 wherein said developing solution contains borax in an amount of at least 10 grams per gallon of developing solution.

11. The developing solution of claim 9 wherein said developer is para-methylamino phenol.

12. The developing solution of claim 9 wherein said developer is pyrogallol.

13. The developing solution of claim 9 wherein said developer is hydroquinone.

No references cited.

1. TRAVIS BROWN, Acting Primary Examiner.

C. E. DAVIS, Assistant Examiner. 

1. A PROCESS FOR THE DEVELOPMENT OF GELATINO SILVER HALIDE ENULSION WHICH COMPRISES DEVOLPING SUCH AN EMULSION IN A DEVELOPING SOLUTION CONTAINING A SULFA COMPOUND SELECTED FROM THE GROUP CONSISTING OF SULFAMETHYLTHIADIAZOLE, SULFANILAMIDE, SULFAPYRIDINE AND SULFATHIAZOLE OR MIXTURES THEREOF, IN AN AMOUNT OF AT LEAST ABOUT 0.1 GRAM PER GALLON OF SAID DEVELOPING SOLUTION. 